Numerous detection and analysis methods for the determination of analytes in bodily fluid samples or other biological samples are nowadays carried out in an automated fashion in a large number in automatic analysis apparatuses, also so-called in-vitro diagnostic systems. To this end, such analysis apparatuses conventionally comprise corresponding analysis or measurement stations as well as a range of transport instruments, for example conveyor belts, transport carousels or transfer arms having gripping instruments for sample vessels, reagent containers and reaction vessels, and furthermore pipetting instruments for the transfer of liquids. The apparatuses furthermore comprise a control unit which, by means of corresponding software, is capable of substantially independently planning and executing the working steps for the desired analyses.
Many of the analysis methods used in such analysis apparatuses operating in an automated fashion are based on optical methods. The determination of clinically relevant parameters, for example the concentration or activity of an analyte, is often carried out by mixing a part of the sample with one or more test reagents in a reaction vessel, which may also be the measurement cell, so as to initiate a biological reaction or a specific binding reaction which causes a measurable change in an optical or other physical property of the reaction mixture.
Conventionally, a sample aliquot is taken from a sample vessel by means of an automatic pipetting instrument and transferred into a reaction vessel. A reaction mixture is prepared by addition of one or more reagents.
Inside the automatic analysis apparatus, the reaction vessels are then typically moved by transfer arms to the various analysis stations. These transfer arms comprise a gripping device for securely taking and depositing the reaction vessels and have an access region defined by the range of the movement mechanics (and optionally further restricted on the control or software side), in which the reaction vessels can be taken or deposited.
After the sample and the reagents have been combined in the reaction vessel, many detection reactions used for the analysis require a certain incubation time, which may last a few minutes. During this incubation time, the reagent components, for example enzymes, enzyme substrates or antibodies, react with the analyte to be detected. Since many detection reactions are temperature-dependent, the incubation of the reaction mixtures is generally carried out in an incubation unit which has a plurality of reception positions for temporary storage of the reaction vessels, in which case the walls of the reception positions may be kept at a predetermined controlled temperature by means of heating/cooling.